Automatic starting mechanism



Sept. 27, 1938. LOEHR ET AL 2,131,403

AUTOMATIC STARTING MECHANISM Filed Jan. 26, 1932 INVENTOR L eslie z. fimuu 6. 43mm wag/aw @607 ATTORNEY Patented-Sept. 27, 1938 UNITED STATES PATENT OFFICE AUTOMATIC STARTING MECHANISM Nevada Application January 26, 1932, Serial No. 589,027

4 Claims.

This invention relates to automatic starting mechanism for internal combustion engines and more particularly to a device for automatically starting an engine on closure of a manual switch such as the ignition switch of the engine, and restarting the same in case of engine stall, as long as said-manual switch is left closed.

Automatic starting devices have heretofore been constructed for use in conjunction with the conventional starting motor and automatic pinion shift, which devices embodied magnetically operated starting switches which were closed when a manual switch such as the ignition switch of the engine was closed, and which were opened by various means responsive to rotation of the engine. In connection with the opening means, difficulty has been encountered in perfecting a device which will open the starting circuit when the engine becomes self-operative but which will not open the starting circuit during the cranking operation. Since it is very undesirable to have the cranking operation interrupted prior to selfoperation of the engine, it is essential for a satisfactory device that this differentiation between cranking and idling conditions of the engine be reliably maintained.

It is an object of the present invention to provide an automatic starting mechanism which is reliable and efiicient in operation and which performs its controlling function unfailingly.

It is another object to provide such a device which employs two separate controlling devices, one for causing the control circuit to be opened when the engine starts, and the other for holding said circuit open as long as the engine is in operation.

A further object of the invention is to provide such a device which is arranged to delay reclosure of the starting circuit while the starting motor is spinning by momentum from the previous actuation thereof.

Further objects and advantages will be apparent to those skilled in this art from the following description taken in connection with the accompanying drawing in which:

Fig. l is a semi-diagrammatic illustration of an electrical system for an internal combustion engine embodying one preferred form of the invention; and

Fig. 2 is a similar view showing a second embodiment of the invention.

Referring first to Fig. 1 of the drawing, there is illustrated an electrical starting system for an internal combustion engine, not shown, comprising a battery I, grounded at 2, and connected by a lead 3 to a series coil 4 of a control relay indicated generally by numeral 5. Relay coil 4 is connected by a lead 6 to a magnetic starting switch indicated generally at l, which switch is connected by a lead 8 to a starting motor SM which is grounded at 9 to complete the starting circuit. It will be understood that the starting motor is intended to crank the engine by means of a conventional form of automatic drive which it is believed to be unnecessary to illustrate.

A control circuit for the magnetic starting switch I is illustrated comprising a manual switch I I which may, as indicated, be the ignition switch of the engine and which is connected by a lead !2 to the battery lead 3. The ignition switch I I is connected by a lead i3 to a solenoid M which when energied causes closure of the starting switch 1. The control circuit is completed from solenoid I4 by a lead I5 which is arranged to be grounded by either of two sets of contacts [6 and I1, contacts l6 being arranged to be operated by the relay 5 and contacts I! being arranged to be operated by another relay indicated generally at l8. The sets of contacts 16 and I1 are arranged in parallel as illustrated whereby closure of either set of contacts completes the control circuit through grounds 21 or 2'6, provided the manual switch II is closed, causing closure of the magnetic switch I and consequent energization of the starting motor.

Contacts I! are normally maintained closed as by means of a light spring 19, and means are provided for opening said contacts in response to rotation of the engine. As here illustrated, this function is performed by the relay 3 which has a coil 21, one end of which is grounded as indicated at 22 and the opposite end of which is connected by a lead 23 direct to a generator G driven by the engine to be started. The opposite terminal of the generator is grounded at 24 to complete its circuit, and the coil 2| is so designed that rotation of the engine atits lowest idling speed, which may be lower than normal cranking speed, will maintain contacts I! open.

Contacts iii are normally open, and means are provided for closing said contacts responsive to energization of the starting system. As here illustrated, these contacts are arranged to be closed by the action of series coil 4 of relay 5 when the starting motor is energized for cranking purposes. Means are provided for opening the contacts I6 responsive to self-operation of the engine, such means being illustrated in the form of a spring 25. The design of the relay 5 and the strength of the spring 25 are so related that the cranking current will maintain the contacts l6 firmly closed, but when the flow of current in the starting circuit is reduced by reason of the relief of the load on the starting motor when the engine becomes self-operative, the spring will overcome the action of coil 4 and open the contacts.

In the operation of this device, and starting with the parts in their normal idle positions as i1- lustrated in Fig. 1, closure of the manual switch l i completes the control circuit from battery I through leads l2 and I3 to the solenoid l4 and through lead !5 and contacts I! to the ground at 26. The consequent closure of the starting switch it completes the starting circuit from battery 1 through lead 3, series coil l, lead 6, switch I and lead 8 to the starting motor and back through the ground connections 9 and 2.

The heavy flow of current through the starting circuit caused by the initiation of the cranking operation strongly energizes the series coil 4, causing closure of the contacts l6 and the consequent completion of a ground connection from the control circuit lead E5 to the ground at 21. The rotation of the engine thereafter causes the generator to energize the coil 2i of relay l8 sufiiciently to open contacts l'i, thus breaking the connection from the control circuit to the ground 26, but the ground connection established through the contacts it maintains the control circuit closed and thus causes the engine to be cranked continuously until starting occurs.

When the engine starts, the cranking load is removed from the starting motor whereby the fiow of current through the starting circuit is greatly reduced. The consequent weakening of the series coil 4 permits the spring 25 to open contacts it, thus opening the control circuit and deenergizing the solenoid l4 whereby starting switch I is opened.

Contacts ill are held open by the generator G as long as the engine is in operation, but should the engine stall, the consequent deenergization of the relay coil it allows the contacts 8'! to close, whereupon the starting operation is automatical- 1y repeated as above described as long as the manual switch ii remains closed.

In Fig. 2 there is illustrated another embodiment of the invention in which means are provided for assisting the generator to open the relay contacts controlled thereby, and also for delaying reclosure of said contacts while the starting motor is spinning by momentum from a previous starting operation.

In this figure the starting circuit, the control a circuit, and the generator relay circuit are all arranged the same as in the embodiment illustrated in Fig. 1, and the elements thereof are similarly numbered. In order to perform the above functions, however, an additional coil 28 is provided on the relay l8, which coil is connected at one end to the ground 22 for the generator coil 2|, and is connected at its other end by a lead 29 to the starting motor lead 8 whereby the coil 28 is placed in shunt with the starting motor when the starting motor circuit is closed by the magnetic switch I. It will be noted that when the switch I is open, the coil 28 is in circuit with the starting motor so as to be energized thereby when the armature of the starting motor is spinning by momentum in its residual field.

In the operation of this embodiment of the invention, closure of the ignition switch ll causes closure of the starting switch I in the same manner as previously described, whereby the starting circuit is energized to cause the engine to be cranked. In this embodiment of the invention, however, closure of the starting switch also causes energization of the shunt coil 28 which thereupon assists the generator coil 2] in energizing the relay IS and causing the contacts I! to open. Since the series coil 4 is of low resistance and inductance and is therefore a quick acting coil, it efiects the closure of the contacts 16 prior to the opening of contacts i? even though the coil l8 be designed to be sufiiciently powerful to open the contacts ll independently of the generator coil 2|. When the engine starts, the contacts l6 are opened by the reduction in starting current as previously described, whereby the starting switch i is opened, and the starting motor and the coil 28 are disconnected from the battery.

In case of a false start, that is, when the engine makes an explosion or two suflicient to release the starting motor from the engine and then dies, immediate reclosure of the starting switch a would merely cause the starting motor to spin without causing the starting gearing to reengage the engine flywheel, since, as is well known in the art, acceleration of the starting motor from a state of rest or of slow rotation is essential to secure the proper engagement of the starter gearing. It has been found that the coil 28 is effective to prevent reclosure of the contacts El while the starting motor is spinning by momentum, by reason of a small amount of current which is generated by the armature of the starting motor as it rotates in the residual field of the motor, whereby the control circuit is maintained open until the starting motor comes substantially to rest. Subsequent closure of the control circuit and of the starting switch I thereby causes restarting to occur in the usual manner.

Although certain forms of the invention have been shown and described in detail, it will be understood that other forms are possible and that various changes might be made in the construction and arrangement of the elements thereof without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an electrical system for internal combustion engines, an engine-driven generator, a starting system including a starting motor and a magnetic switch therefor, a control circuit for said magnetic switch including two circuit-closing devices in parallel, one of which is normally closed and the other normally open, means energized by closure of said magnetic switch for closing the second said device, means energized by said generator for opening the first said device, means also energized by closure of the magnetic switch for assisting the generator means in opening the first said device, and means for overcoming said closing means and opening said second device when the engine becomes self-operative.

2. In an electrical system for internal combustion engines, an engine-driven generator, a. starting system including a starting motor and a magnetic switch therefor, a control circuit for said magnetic switch including two circuit-closing devices in parallel, one of which is normally closed and the other normally open, means energized by closure of said magnetic switch for closing the second said device, means energized by said generator for opening the first said device, means also energized by closure of the magnetic switch for assisting the generator means in opening the first said device, and means for overcoming said closing means and opening said second device when the engine becomes self-operative, said assisting means being arranged to hold said first device open, in case the engine stops, until the starting motor comes substantially to rest.

3. In an electrical system for internal combustion engines, an engine-driven generator, a starting system including a starting motor and a magnetic switch therefor, a control circuit for said magnetic switch including two relays with their contacts in parallel, one relay being normally closed and the other normally open, the first relay having a coil energized by said generator for opening its contacts when the engine is rotated, the second relay having a coil in series with the starting motor for closing its contacts when the motor cranks the engine, and a spring for opening said second relay when its coil is weakened by the relief of the load on the starting motor when the engine starts, said first relay also having a coil in shunt with the starting motor during the starting operation for assisting the generator coil to open its contacts.

4. In an electrical system for internal combustion engines, an engine-driven generator, a starting system including a starting motor and a magnetic switch therefor, a control circuit for said magnetic switch including two relays with their contacts in parallel, one relay being normally closed and the other normally open, the first relay having a coil energized by said generator for opening its contacts when the engine is rotated, the second relay having a coil in series with the starting motor for closing its contacts when the motor cranks the engine, and a spring for opening said second relay when its coil is weakened by the relief of the load on the starting motor when the engine starts, said first relay also having a coil in shunt with the starting motor during the starting operation for assisting the generator coil to open its contacts, said assisting coil being in circuit with the starting motor when the magnetic switch is opened, whereby spinning of the starting motor by momentum retains sufiicient magnetism in said first relay to prevent reclosure of its contacts.

LESLIE K. LOEHR. WAYNE E. BURDICK. 

